Method of producing an image on a printing screen

ABSTRACT

Methods of producing an image on a printing screen are described. The method uses inkjet printing technology to form an image on the screen using a computer to screen or computer to plate imaging technique. According to particular embodiments a specially formulated emulsion is used in which the emulsion is mixed with a cross-linking agent to create a self curing image.

This application claims benefit of U.S. Provisional Application No.60/422,175 filed Oct. 30, 2002.

FIELD OF THE INVENTION

This invention relates to a computer-to-screen (CTS) imaging system andmore particularly to systems and methods for reproducing a digitizedimage on a silk screen stencil or lithography plate.

BACKGROUND

In certain printing processes, such as screen printing, a stencilcontaining, for example, a negative of a desired image is required. Inthe printing process this stencil is placed on the surface of thecarrier to which the image is to be transferred and ink is imprintedthrough the stencil.

There are numerous existing techniques for preparing the stencil withone of the most common involving the use of a photographically preparednegative which is placed over a screen onto which has been applied aphoto activatable emulsion. Such emulsions are typically sensitive toultraviolet radiation and in this process the screen is exposed toultraviolet radiation such that the portions of the screen not blockedby the photographic mask are activated. Typically the emulsion is watersoluble or at least soluble in a known solvent and in the developingprocess the non-activated emulsion is removed from the screen therebyleaving a negative of the image. It will be apparent to one skilled inthe art that the process can be used to generate a positive of theimage.

With ongoing advances in digitized images it is particularlyadvantageous to directly convert an image from a computer to thestencil. Several methods of performing this conversion have beendeveloped in as much as computer to screen imaging is seen as a methodof allowing an operator to modify images or to prepare images based ondrawings or other two dimensional formats utilizing a scanningapplication. Recent improvements in the work flow associated with theactual printing process and the use of digital imaging in thepreparation of graphics has made the need for a true CTS an importantenabler in order to realise cost benefits produced by othertechnological improvements.

The prior art includes numerous methods of preparing stencils using aCTS imaging process. These include a laser ablation system in which alaser is used to remove material from a fully blocked screen with thenon-removed material creating the negative image.

It is also known to use laser direct imaging in which a laser is scannedpoint by point over a silk screen coated with a photo activated emulsionto create an image in that emulsion.

Another known method is an optical micro electrical mechanical system(MEMS) technique wherein a series of independently controllable mirrorsare used to direct light onto a clearly defined and limited area of ascreen which has been coated with a photo-activatable emulsion. Oncethis area has been activated the mirrors are directed to an adjacentblock of the screen and the process repeated. In this manner a fullimage can be constructed block by block.

U.S. Pat. No. 5,580,698, which issued Dec. 3, 1996 to Anderson,describes a system for producing fine printing patterns on largeserigraphical printing frames utilising a type of mirror arrangement. Inthis patent a laser beam is directed through a series of mirrors to ascanner which is moved laterally and longitudinally along sections of ascreen and the light source is modulated in order to produce a pattern.The light source is a ultraviolet laser and the pattern is generated ina dot by dot sequence.

In U.S. Pat. No. 6,178,006 a system for plotting a computer storedraster image on a plain photosensitive record carrier is discussed. Inthis patent the area to be prepared is subdivided into numerous subareas and each one is processed sequentially.

Each one of these known methods has a number of serious limitations. Forexample, debris re-deposition is an issue with the laser ablation andlike the laser direct image method it is a point by point process. Thislimits the exposure rate of both methods. Mechanical instability andreliability will be inherent issues with the MEMS method. In fact, thiswill be true for any projection method.

Ink jet masking represents another body of prior art relating to stencilformation. In one example of this technique a negative of the image tobe printed is created by using an ink jet to deposit wax onto a screencoated with a photo activatable emulsion. The deposited wax blocks thelight when the screen is subsequently exposed. Once exposure iscompleted the wax is removed to produce the final printable image. Anexample of an ink jet masking approach is disclosed in U.S. Pat. No.5,875,712 which issued Mar. 2, 1999 to Ericsson et al. In the Ericssonet al. patent, carbon powder is selectively deposited using a printerunit where the carbon powder prevents light from reaching the screenand, after the exposure step, subsequent rinsing removes all of theunexposed material.

Canadian Patent 2088400 which issued Jan. 23, 1994 to Gerber ScientificProducts, Inc. also teaches the use of an inkjet to deposit a blockingagent onto a screen mesh to produce a stencil. Canadian Patent 2088400can not be applied to an inkjet process if a typical emulsion is used asthe blocking agent. A screen emulsion can have a viscosity of over10,000 cps and up to 65% of its volume can be made up of solid particles(fillers). The purpose of such solids are two fold, (a) they make thecured emulsion more resilient to the rigors of the printing process and(b) they improve the definition and hence the overall quality of theimage. These particles can range in size from 3 to 100 microns and canand do agglomerate into larger partides. A typical ink jet can deposit afluid if its viscosity is less than 20 cps. Therefore even if the jetscould discharge an emulsion with a viscosity of 10,000 cps at thedesired resolution, the solids present in the emulsion will quickly plugthe jetting nozzles. Hence the inability of CA 02088400.

EP-A-0492351 also to Gerber Scientific Products, Inc. teaches the use ofan inkjet to create a light-blocking mask on a screen that had beenpreviously coated with a light sensitive emulsion. On exposure to UVlight the areas which are not blocked are rendered insoluble to water asa result of additional cross-linking of the polymer. Subsequentprocessing according to the known art will produce a stencil. In thecase of EP-A-0492351 there is the further requirement to expose theun-masked regions to UV light. This represents an added complexity.

U.S. Pat. No. 5,380,769 which issued Jan. 10, 1995 to Titterington etal. teaches that a chemical deposited by an inkjet can be used insteadof UV light to produce additional cross linking. This is simplyconfirmation of the established knowledge that crosslinking can bedriven by a chemical process. In U.S. Pat. No. 5,380,769 a chemicalcuring agent is applied to a phase-change base ink. The cured region ofthe ink is then transferred to the image substrate in a secondaryprocess. Any ink in its liquid phase will have a natural tendency to wetbeyond the point of contact when deposited onto an absorbing medium. Forgood image reproduction this tendency must be inhibited. The standardinhibitor method is to use a paper coated with anti-wetting chemicals.The solution that U.S. Pat. No. 5,380,769 teaches relies on the factthat an ink in its solid phase is less mobile than when it is its liquidphase. Therefore, if an ink is used which immediately becomes solid onceit is deposited onto an absorbing surface, the tendency for the ink towet is reduced. This phase transition, liquid to solid, is a physicalchange. It can be easily reverse and it does not change the chemicalnature of the ink, i.e., if the ink is soluble in water before the phasechange it will remain soluble in water after the phase change. Theadvantage of this approach is it allows for the use of a less expensiveun-coated paper for the production of high quality colour images.However the requirements of a screen emulsion are fundamentallydifferent.

EP 0909642 published Mar. 12, 2003 to Autotype International Limitedteaches that post processing of the finished stencil with aqueouspotassium carbonate can increase the durability and resilience of thestencil. However the chemical as used plays no role in the crosslinkngprocess nor does it improve the image resolution.

In stencil preparation cured emulsion must serve many distinct purposes.It acts as a gasket to inhibit the spread of ink between adjacentregions of the printed surface. It must allow the screen mesh toefficiently transport the ink from its top surface to the substrate. Theemulsion must not only evenly wet the surface of the mesh, it must alsopermeate the complete body of the mesh. An emulsion must be capable ofproducing an image with good edge definition and this image must becapable of withstanding the physical wear and tear of the screenprinting process. These requirements are contrary to the properties ofan ink. Therefore the art that is taught in U.S. Pat. No. 5,380,769 isnot applicable to a screen emulsion.

Although CA 02088400, EP-A-0492351, U.S. Pat. No. 5,380,769, EP 0909642in combination teaches the general art of producing a stencil from adigital file but the stencils produced by these methods are generallyunsatisfactory. There are many factors that make producing a stencil bythis known art challenging. For example CA 02088400 cannot be used witha standard screen emulsion. The phase change as described in U.S. Pat.No. 5,380,769 can only be used to control the resolution of the imagebut it does not improve the durability of the ink. In the Autotype,International processes (U.S. Pat. No. 6,539,856 B2 and EP 0 909 642 B1)the curing agent induces a chemical phase change but no discussion onits benefits to the resolution or the durability of the final stencil isprovided. Also the role of the solid in the curing process is notconsidered. It is the purpose of this invention to describe how thisstate of the known art can be improved upon and lead to the productionof a stencil which meets industry standards.

SUMMARY OF THE INVENTION

The present invention seeks to provide a method and apparatus that willreduce the tendency for an inkjet applied curing agent to spread beyondthe point of initial contact and thus improve image definition. It isalso within the scope of this invention to show how additional solidscan be incorporated within the body of the emulsion as it cures usingthis method and apparatus. It is the further purpose of this inventionto show how to use optical curing and chemical curing in combination torapidly and economically produce a high resolution stencil. It is also apurpose of this invention to provide a method and apparatus to depositan emulsion with an inkjet. The invention, further seeks to provide amethod and apparatus that will incorporate a solid into the body of anemulsion as it cures. It is a further purpose of this invention toprovide a method and apparatus that can deposit a self-curing emulsionthat manufacturers its own solids within its body.

It is also the purpose of this invention to show how the creation ofagents during a curing process can inhibit the diffusion of the curingagent or emulsion.

Accordingly, the present invention provides a simple and efficientmethod of generating a stencil using a computer to screen imagingsystem.

Therefore, in accordance with a first aspect of the present inventionthere is provided a method of producing an image on a printing screencomprising the steps of: coating the printing screen with a watersoluble blocking agent; providing a curing agent that can interact withthe blocking agent to create insoluble agents; selectively applying thecuring agent to the blocking agent in an image wise manner where theimage becomes water insoluble; and washing away uncured blocking agent.

In accordance with a second aspect of the invention there is provided amethod of producing an image on a printing screen comprising the stepsof selectively depositing a diluted and filtered photopolymer emulsionon the printed screen; and curing the selectively deposited image with acuring agent.

According to a third aspect of the invention there is provided a methodof producing an image on a printing screen comprising: providing acuring agent that can interact with a blocking agent to create insolubleagents premixing the curing agent with a photopolymer emulsion; andselectively depositing the curing agent and emulsion on said printingscreen wherein said emulsion is self curing on placement on the screen.

In accordance with a preferred embodiment of this aspect of theinvention the crosslinking agent is deposited using an inkjet printer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tothe attached drawings wherein:

FIG. 1 is a inkjet deposit method according to the prior art; and

FIG. 2 shows a cross sectional view of a deposition system according tothe invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a prior art method as described in aforementionedU.S. Pat. No. 5,875,712 in which an inkjet printer is used to depositlight blocking material onto an emulsion coated screen where thematerial prevents light from reaching the screen so that the unexposedemulsion underneath the blocking material can be washed away.

The present invention makes use of inlet printing technology in acomputer to screen (CTS) imaging system. It is well known that digitalimaging techniques can be used to store, in a computer, digital imagesof patterns which are to be reproduced on a silk screen or a lithographyplate for generating a screen or plate. The concept is analogous to theproduction of a printed image on a sheet of paper wherein “ink” isejected onto the paper as a reproduction of the image stored in thecomputer. In the present invention this technology is extended todepositing patterns onto a silk screen or lithographic plate usingvarious techniques. In one embodiment the inkjet technology is combinedwith the continuing developments in the LED technology to produce theimage. In a previous application (U.S. Provisional 60/304,073) an LED isused to create an image directly on the screen without the use of aphotomask. In that application the screen is pre coated, exposed to theLED source and then developed (washed with water to remove theundeveloped emulsion) thus leaving the desired image. The previoustechnique is considered to be a wet and light activated stencilproduction. The contents of U.S. Provisional Application 60/304,073 isincorporated herein by reference.

The present invention relies on three basic principles.

-   1. The mobility of a liquid through a medium such as a dry emulsion    is inversely proportional to the particle (solid) content 6f that    liquid: The solid content will be highest nearest the point of    injection. Filtration with a filter paper operates on this    principle.-   2. The ability to increase the solid concentration during the    crosslinking process: The durability and the sharpness of an image    on a screen stencil is dependent on its solid content. The greater    the solid content the better these properties will be.-   3. A strong correlation and the co-location of the solid    manufacturing and the crosslinking processes: The solid is used as a    lattice frame-work around which the water insoluble polymer is    formed. Therefore it is highly advantageous to co-locate and    encourage an inter-dependency of these processes.

If these three principles can be combined in a chemical curing agentthat is used to prepare a screen stencil, it will produce a sharp, highresolution and durable image for the following reasons. The reducedmobility of the curing agent will reduce the tendency to defocus theimage, principle (1). The increase in solid content will add toughnessto the emulsion, principle (2). The colocation and strong correlationbetween the crosslinking process will bias the polymer formulation toareas where the solid concentration is highest, therefore the polymerwill form preferentially at the point of injection, principle (3)

The conversion of a water soluble polymer to a water insoluble polymeris the goal of any screen stencil formation process. A redox reactioncan be used to induce such a conversion. The oxidation of the ferrousion (Fe²⁺) to the ferric ion (Fe²⁺) is but one example of such areaction. This is demonstrated by using the following protocol. A screenwas coated with a commercially available standard SBQ photopolymerscreen emulsion using the accepted industry method. Examples of suitableSBQ photopolymer screen emulsions are Majestic 067 and Majestic 057.Solutions of 1:50 by weight of FeSO₄, CuSo₄, FeCl₂ and NaCl in waterwere deposited onto screens and left to dry in the dark in air and atroom temperature. On subsequent immersion in water or by using thestandard industrial procedure only those regions-that were covered bythe ferrous ion, FeSO₄ or FeCl₂, were found to be insoluble in water.Moreover the screens could be reclaimed using the standard industrialmethod.

It is well known that in the presence of O₂ the ferrous ion is readilyoxidized to the ferric ion via a redox reaction. The rest of thisdiscussion will be focussed on the use of FeSO₄ to form a stencil andits relationship to the three principles just outlined. FeSO₄ is solidthat is very soluble in water. However in the presence of oxygen it isreadily converted to Fe₂O₃, a solid that is very insoluble in water. Itis now apparent why FeSO₄ would represent an optimal chemical curingagent for a screen emulsion. Its high solubility in water allows for itseffective and even dispersion in a water-soluble emulsion. As theemulsion dries the Fe²⁺ ion comes in contact with either dissolved O₂ oratmospheric oxygen. This occurrence readily promotes the redox reactionthat converts Fe²⁺ to Fe³⁺. This reaction initiates crosslinking, and inthe same location, concurrently forms the solid Fe₂O₃. This solid nowbecomes the lattice around which the insoluble polymer forms. Finally,the solid Fe₂O₃ partides inhibits the further spread of Fe₂SO₄ from thepoint of initial application thus maintaining the image resolutionduring the wetting process.

The previous discussion described how it is possible to manufacture asolid filler during the curing process. Given this, there are othernovel variations on this generic theme. In the previous example a singlechemical FeSO₄ could perform both function. It is possible that the useof a single chemical may not always be preferable.

The preferred curing agent may not lead to solid formation or thepreferred solid may not initiate the curing process. If this is the casea variation on this theme can be implemented. It utilizes the fact thatcolour production using an inkjet involves co-locating the three primarycolours magenta, cyan and yellow. Therefore the magenta and the yellowink, for example, in a standard inkjet can be replaced with chemical Aand B such that when they are combined an insoluble solid X is produced.At the same time a curing agent C placed in the cyan head can beco-located. The appropriate software could then be used to co-locate theappropriate amount of A, B and C in the appropriate concentrations suchthat as X is being generated by A and B, C concurrently cures theemulsion. As an example A could be Ca(HCO₃)₂ and B could be NaOH. Thesechemicals when combined produce the insoluble solid CaCO₃ and solubleNa(HCO₃) in solution. Any Na(HCO₃) that is not incorporated in the solidwill be washed away during the wash out phase of making a stencil.

The curing agent C need not be a chemical. It could be photons. This isparticularly advantageous since most screen emulsions are designed to bephoto-activated with UV photons Therefore an array of UV LEDs or similarlight sources could be used instead of C or in combination with C todrive the necessary crosslinking. The photons need not be UV. IR orVisible could also be used to photo activate the chemical curing agent Cor photo activate the reaction between A and B. Alternatively, suchphotons could be used to determine the kinetics of C interacting withthe polymer or A reacting with B by providing additional translationvibration or electronic energy.

Given that a method of dynamically integrating a chemical cure with aphoton cure has been established, there may be some situations where itwould be advantageous to intelligently and dynamically select betweenthese methods on the same image for a given emulsion. It is not uncommonto have areas of high and low resolution in the same image. If one canintelligently and dynamically separate the areas of low and highresolution one can use the optimum curing source for that specific areaof the image.

It is relatively simple and inexpensive to produce an inkjet head with2400 dpi capability. This is a difficult and capital expensive task todo with LEDs. Conversely a chemical cure using an inkjet at highresolution could consume a large quantity of an expensive chemical, butonce the LED head has been produced its operational cost is relativelyinexpensive. Finally it is relatively simple to control the operationalcharacteristics of a long (<100 cm) LED array head containing manythousands of LEDs. It is a non trivial problem to control the jettingcharacteristics of more than 500 nozzles simultaneously.

If the interchange between LEDs and inkjet cure can be performeddynamically, i.e. one can use the optimum curing agent for a prescribedportion of the image. The net effect of this will be a reduction inoperational cost and an increase in processing speed whilst maintainingthe desirable image quality. The costly chemical will only be used whereit is needed and full advantage will be taken of the long LED array torapidly cure the low resolution portions of the image.

As stated earlier CA 02088400 as described is not applicable to astandard screen emulsion with typical inkjets. Even if such jets werecapable of jetting the very viscous material (10,000 cps) the nozzleswill quickly become blocked by the high particle content of a standardemulsion. The application of principles 2 and 3 could be used to makethe art described in CA 02088400 applicable to a screen emulsionformulation. As discussed previously the purpose of the solid is toprovide a lattice framework around which the water insoluble polymer isformed. If principle 2 and 3 is applied to an emulsion which has had itssolid removed before jetting, an equivalent solid will be manufacturedduring the curing process. The scientific basis for this was developedas follows.

A 3.1 mixture of a commercial SBQ photopolymer and water was prepared.This mixture was placed in a centrifuge for 15 minutes. The liquid andthe solid separated into two distinctive components. The liquid wasremoved and passed through a 3 micron cellulose filter. Measurementswith a particle size monitor confirmed that the maximum particle size inthe filtered emulsion were less than 5 microns. This can be compared toaverage particulate sizes of greater than 40 microns in the standardformulation. This mixture was heated in a water bath to 90° C. At thistemperature the measured viscosity was 4 cps. A mixture containing 1part FeSO₄ (1:25, FeSO₄:H2O) to 1 part of C₂H₅OH was deposited in theform of a halftone image onto a screen coated with this hot mixture. Itwas left to dry in the dark in air and at room temperature. The screenwas then developed as per the industry standard. There was no obviousdifference between the stencil formed from this mixture and that formedfrom an unheated mixture.

A sample of SBQ photopolymer with no added solid filler was secured froma commercial supplier. A small quantity of a water base dye was added tothis polymer to improve contrast for our experimental purposes. A screenwas coated and dried in the usual manner. A mixture containing 1 partFeSO₄ (1:25, FeSO₄:H2O) to 1 part of C₂H₅OH was deposited in the form ofa halftone image on the screen. It was left to dry in the dark in airand at room temperature. The screen was then developed as per industrystandard. Again there was no obvious difference between the quality ofthis image and one produced by the filtered and heated emulsion.

As a final example 0.05 gms of FeSo₄ was dissolved directly in 10 gms ofthe photopolymer mix. Provided this mixture remained in the dark and notexposed to air it remained in a liquid state. If a screen was coatedwith this mixture and left to dry in the dark in the presence of air the“mixture” on the screen became insoluble in water. However the screencould be reclaimed as before.

It is clear from the foregoing that

-   1. A “solid free” or a low particle size emulsion can be formulated    to meet the viscosity requirement of a typical inkjet.-   2. This emulsion formulation is stable at the temperature needed to    reduce its viscosity to a level compatible with the requirements of    an ink jet.-   3. This emulsion can be converted from water soluble to water    insoluble.-   4. This emulsion can be processes according to principle 2 and 3 to    produce a stencil.-   5. The curing agent can be added directly to the emulsion.

It must follow that if a solid free version of this emulsion is placedin one colour chamber of a typical inkjet it should be possible toco-locate this emulsion with a curing agent such as FeSO₄ that had beenplaced in a second chamber. The deposition can be made in an image wisemanner and the solid will be produced in accordance with principles 2and 3 during the curing process. This solid will form the lattice framework for the water insoluble polymer. With this method a print readystencil can be prepared on an uncoated screen from a standard emulsion.

Naturally all of the variations and combinations of photon and chemicalcure that was previously described can be applied to this method. Thatis a combination of LEDs and inkjets can be used to manufacture thesolid and supply the curing agent.

There is further possibility with this method. Provided FeSO₄ is in anoxygen free (or oxygen deficient) environment, formation of the ferricion is inhibited. Therefore a mixture of the photopolymer and FeSO₄ isstable provided it is kept in a dark oxygen free (or oxygen deficient)environment. However if a drop of this mixture is placed on a surfaceand allowed to dry in atmospheric oxygen in the dark it will form awater insoluble polymer. The drying action of the emulsion will bringthe FeSO₄ in contact with atmospheric oxygen and hence initiate theredox reaction. A sealed inkjet reservoir meets the requirement of beinga dark oxygen free (or oxygen deficient) environment. Therefore aninkjet system could be used to deposit the mixture of FeSO₄ andphotopolymer in the form of an image. This method can therefore preparea print ready stencil on a blank screen in one step.

The terms curing and curing process for the sake of the presentapplication include the process wherein a curing agent or curing agentscreates, co-locates and incorporates additional and soluble particulate(strengthening agents) by the interaction of one or more elements eitherin combination or singularly with the blocking agent or in combinationor singularly with themselves at the location where the blocking agentbecomes water insoluble.

It is obvious that someone skilled in the art could combine any of theabove proposals to produce a stencil production system that is either“dry” or “light free” or “wet” to meet the specific requirements of anemulsion type. Inkjets are now widely available for dispensing a varietyof fluids. Therefore the above system could be configured to dispenseinks (Magenta, Yellow and Green), emulsion and activators combinationsand hence function as either a standard inkjet printer or a “DigitalStencil Printer”.

Naturally anyone skilled in the art would recognise that any lightsource with the equivalent properties of the LED arrays could be used toreplace the LEDs. However the use of LEDs offer the following twoadvantages. It should be possible to co-locate the positions of inkjetspots and the LEDs position on the screen or plate and one could easilytune the spectral properties of the LEDs to optimise the curing process.In addition other emulsions and light free activators combination couldbe used.

FIG. 2 is a high level representation of a screen 16 which, depending onwhich of the above described embodiments is used, is coated with a watersoluble blocking agent or is uncoated. A nozzle 12 such as an inkjetprinter is used to selectively deposit the curing agent or agents. Inthe case of multiple agents the inkjet printer will comprise means todeliver the additional elements of the curing agent. Although the fluiddelivery system is defined as being an inkjet it will be apparent to oneskilled in the art that other delivery systems may be used in place ofthe inkjet printer. In FIG. 2 element 18 is an LED module or similardevice used to provide the protons in the embodiments in which protonsare used in the curing process. IR, visable or UV emitting LEDs can beused. Other light sources can also be used.

An arrangement such as shown in FIG. 1 is contemplated for the deliveryof the curing agents selectively or spanning the entire screen.

In summary, the present invention provides methods of: preparing astencil without pre or post processing; preparing a stencil which useschemical to define image and light to fix image; preparing a stencilwith an emulsion that contains no solid/filler; preparing an emulsionwhich uses/contains a jettable “solid/filler” or chemical which has thesame effect as a “solid/filler”; preparing a stencil by using a redoxpolymerisation process to cure the emulsion; preparing a silk screenthat does not need light to define image; preparing a stencil with aself curing emulsion; and preparing a stencil wherein the screen isre-claimable or re-usable.

Although particular embodiments of the invention have been described andillustrated it will be apparent to one skilled in the art that numerouschanges can be made without departing from the basic concept. It is tobe understood, however, that such changes will fall within the fullscope of the invention as defined by the appended claims.

1.-41. (canceled)
 42. A method of producing an image on a printingscreen, comprising: depositing an emulsion on the printing screen in animage-wise manner; depositing a first agent with the emulsion, the firstagent being a chemical in liquid solution and that forms solids uponreaction with a second agent; providing the second agent to thedeposited emulsion; and providing a curing agent to the emulsion,whereby the first agent forms solids within the emulsion upon reactionwith the second agent, and whereby the emulsion cures about the solidsso as to inhibit spread of the emulsion.
 43. The method of claim 42wherein the second agent is atmospheric oxygen, and wherein the firstagent is maintained in an oxygen deficient environment until depositedwith the emulsion.
 44. The method of claim 43 wherein the first agent isFeSO₄.
 45. The method of claim 43 wherein the first agent is pre-mixedin solution with the emulsion such that depositing the first agentoccurs as part of depositing the emulsion.
 46. The method of claim 45wherein the first agent is FeSO₄.
 47. The method of claim 42 wherein thesecond agent is a chemical in liquid solution, and wherein the methodcomprises the further step of depositing the second agent with theemulsion.
 48. The method of claim 47 wherein the first agent is CaCl andthe second agent is NaCO₃.
 49. The method of claim 42 wherein the curingagent comprises photons emitted by a Light Emitting Diode.
 50. Themethod of claim 42 wherein the emulsion is a diluted and filteredphotopolymer.
 51. The method of claim 50 wherein the emulsion and thefirst agent are each provided in a separate well of an inkjet cartridge,and wherein the emulsion and the first agent are depositedsimultaneously using an inkjet printer.
 52. The method of claim 51wherein the emulsion and the first agent are deposited based on acomputer-to-screen imaging system.
 53. The method of claim 51 whereinthe curing agent is a chemical in liquid solution, wherein the curingagent is provided in a separate well of the inkjet cartridge, andwherein providing the curing agent to the emulsion comprises depositingthe curing agent using the inkjet printer simultaneously to depositingthe emulsion.
 54. The method of claim 51 wherein the second agent isatmospheric oxygen, and whereby the first agent forms insoluble agentsupon deposition of the emulsion on the printing screen.
 55. The methodof claim 54 wherein the first agent if FeSO₄.
 56. The method of claim 55wherein the FeSO₄ and the atmospheric oxygen together act as the curingagent.
 57. The method of claim 51 wherein the second agent is a chemicalin liquid solution provided in a separate well of the inkjet cartridge,and wherein the method comprises the further step of depositing thesecond agent simultaneously with the emulsion.
 58. The method of claim57 wherein the first agent is CaCl and the second agent is NaCO₃. 59.The method of claim 51 wherein the curing agent comprises photonsemitted by a Light Emitting Diode.